Delays in railroad shipping have cost Minnesota corn, soybean and wheat farmers nearly $100 million and cut deeply into the value of grain still in storage at farms across the state, according to a University of Minnesota report released at an agricultural freight conference Thursday.

The Minnesota Department of Agriculture organized the one-day conference in Alexandria to bring farm groups, elevator operators and railroad officials together to discuss transportation delays across the Upper Midwest in recent months that have made it difficult to deliver grain to waiting customers. Critics of the railroads often blame the increase in oil shipments from North Dakota, while the railroads point instead to the brutal winter and congestion at key rail hubs.

The study - by Edward Usset of the university's Center for Farm Financial Management - estimated that the rail delays cost Minnesota corn growers $72 million in lower prices from March to May, an average loss of 30 cents per bushel. He put the revenue losses at $18.8 million for soybean growers, or 40.5 cents per bushel, and $8.5 million for wheat growers, or 41 cents per bushel.